Nitrate-nitrogen (nitrate)

A highly soluble compound of nitrogen and oxygen with the chemical formula NO3-. Ammoniacal nitrogen is converted to nitrate nitrogen in soils, from where it can then leach into waterways. Nitrate is a plant fertiliser, however, due to its high solubility in water, it is one of the most common contaminants in rural and suburban areas. It is also toxic at very high concentrations and is measured in mg/L.